Discharge tube



H. J. SPANNER ET AL;

DTSCHAHGE TUBE Original Filed Oct. 19, 1929 Patented Sept. 8, 1936 UNITED STATES DISCHARGE TUBE Hans J. Spanner and Edmund Germer, Berlin, Germany, assignors, by mesne assignments, to

said Hans J. Spanner Application October 19,

1929, Serial N0. 400,805.

In Germany May 4, 1929. Renewed December 10 Claims.

This invention relates to discharge tubes, such as light tubes and ultra-violet ray tubes or radiators, and has for an object the provision of ignition means for facilitating the creation of the discharge in low-voltage tubes'oi the character described.

The accompanying drawing shows one form of discharge tube to which our invention is applied.

Tube l is provided at each end with two elec trodes, one of which 2 serves as an auxiliary anode and the other 3 acting alternately as cathode and anode when connected to an alternating current. The lead-in wires of the electrodes 3, 3 are respectively soldered to conducting rings 4, 4 which are mounted on the exterior of the tube near the ends, and almost connecting the rings is a thin conducting strip 5 having a gap 6, which is about of the length between the rings. The strip 5 may be of any suitable conducting metal or aquadag.

The gap 6 acts as a capacity between the electrodes 3, 3 so that when alternating current is applied the discharge between them is readily created. a

In employing direct current it is necessary, of course, to give the strip a certain polarity, in which case one end of the strip is connected to the anode, and a positive potential applied thereto. The anode in this case should have no special activation, and should preferably be made oi a sheet of neutral or electro-negative metal or carbon; it may also comprise an electro-negative metallic compound such as zirconium oxide, which is preferably mixed with nickel powder.

The electrodes l, 3 comprise a carrier body I of wire having a coating 8 of a mixture of a free electropositive emitting metal, such as barium and strontium, and some other substance which also has some electron emission and an extremely small heat conductivity at the operating temperatures, such as calcium zincate.

Having described our invention, we claim:

1. In a discharge tube having auxiliary anodes and electrodes acting alternately as anode and cathode under alternating current load, conductors connecting said electrodes and extending toward each other and having a gap between their ends approximately ten per cent of the distance between the electrodes.

2. A discharge tube comprising an evacuated elongated glass vessel containing auxiliary anodes and other electrodes at their ends, the latter acting alternately as anode and cathode under alternating current load, a conducting ring connected to each oi said electrodes mounted near the ends of said tube, and conducting members connected to said rings and separated from each other by a short gap.

8. A discharge tube. comprising an evacuated U-shaped vessel having at its ends auxiliary anodes and electrodes acting alternately as anode and cathode under alternating current load, a conducting ring connected to each of said electrodes mounted near the ends of said tube, and a conducting strip almost connecting said rings, the gap in said strip being about ten per cent of the distance between rings.

4. A discharge tube comprising an evacuated U-shaped vessel havirm at its ends auxiliary anodes and electrodes acting alternately as anode and cathode under alternating current load, a conducting ring connected to each of said, electrodes mounted near the ends or said tube, and a line of aquadag almost connecting said rings, the gap in said line being about ten per cent of the length of said line.

5. A discharge tube having activated solid electrodes acting alternately as anode and cathode under alternating current load and means for starting a discharge between said electrodes comprising a conductive layer on the wall of the containing vessel extending along the whole length of the said vessel, except for a non-conductive gap in close vicinity of one electrode, both parts of said divided layer being connected to corresponding sides of the circuit of the tube.

6. A discharge tube as claimed in claim 5. wherein auxiliary electrodes are provided in the vicinity of at least one o! the activated electrodes.

7. A discharge tube as claimed in claim 5, both parts of the conductive layer being enlarged near the poles of the vessel by a conducting ring.

8. A discharge tube as a source of visible and ultra-violet radiation having at least one activated solid electrode acting as a cathode tor direct current operation, and means for starting a discharge between said cathode and the anode comprising a conductive layer on the wall of the containing vessel, extending along the whole length of the said vessel except for a non-conductive gap in close vicinity of the negative pole, both parts oi the said divided layer being connected to corresponding sides oi the circuit of the tube.

9. A discharge tube as claimed in claim 8. both parts 01' the conductive layer being enlarged nearthe poles of the vessel by a conducting ring.

10. An electrical discharge device having solid electrodes, at least one of which is a cathode of the type which is emissive when cold, spaced apart within a containing vessel, and means for facilitating thestarting of a discharge within said device comprising a conductive layer on the wall of the vessel extending along the length thereof but leaving a non-conductive gap near said cathode, and said conductive layer having substantial area beyond the gap connected to the opposite electrode.

HANS J. SPANNER.

EDMUND GERMER. 

